diff --git a/src/Controller/Booking/CreateStep1Controller.php b/src/Controller/Booking/CreateStep1Controller.php
index f225675..d9fb319 100644
--- a/src/Controller/Booking/CreateStep1Controller.php
+++ b/src/Controller/Booking/CreateStep1Controller.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Controller\Booking;
 
+use App\Exception\NoRoomsAvailableException;
 use App\Form\BookingCreateStep1Type;
 use App\Service\BookingService;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
@@ -32,7 +33,13 @@ class CreateStep1Controller extends AbstractController
     #[Route('/bookings/create', name: 'app_booking_create_step_1')]
     public function index(Request $request): Response
     {
-        $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+        try {
+            $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+        } catch (NoRoomsAvailableException $e) {
+            $this->addFlash('error', 'Leider sind für diese Reise aktuell keine Zimmer verfügbar.');
+            // TODO: Redirect to travel listing or hotel details page
+            throw $this->createNotFoundException('No rooms available for this travel.');
+        }
 
         // Get or create baseline snapshot for change detection
         $oldRoomSelectionSnapshot = $this->bookingService->getOrCreateBaselineSnapshot($request, $bookingCreateDto);
@@ -83,7 +90,12 @@ class CreateStep1Controller extends AbstractController
     #[Route('/bookings/create/room-summary', name: 'app_booking_create_step_1_room_summary', methods: ['POST'])]
     public function roomSummary(Request $request): Response
     {
-        $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+        try {
+            $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+        } catch (NoRoomsAvailableException $e) {
+            // For HTMX requests, return a simple error message
+            return new Response('<div class="text-red-700 p-4">Keine Zimmer verfügbar</div>', 400);
+        }
 
         // Process the form to update the DTO with the latest room selection
         $form = $this->createForm(BookingCreateStep1Type::class, $bookingCreateDto, [
diff --git a/src/Controller/Booking/CreateStep2Controller.php b/src/Controller/Booking/CreateStep2Controller.php
index 1269772..b095a70 100644
--- a/src/Controller/Booking/CreateStep2Controller.php
+++ b/src/Controller/Booking/CreateStep2Controller.php
@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace App\Controller\Booking;
 
 use App\Controller\Traits\HtmxControllerTrait;
+use App\Exception\NoRoomsAvailableException;
 use App\Form\BookingCreateStep2Type;
 use App\Form\Model\BookingCreateDto;
 use App\Form\Model\ParticipantDto;
@@ -38,9 +39,15 @@ class CreateStep2Controller extends AbstractController
     #[Route('/bookings/create/participants', name: 'app_booking_create_step_2')]
     public function participants(Request $request): Response
     {
-        $bookingCreateDto = $this
-            ->bookingService
-            ->getOrCreateBookingCreateDto($request);
+        try {
+            $bookingCreateDto = $this
+                ->bookingService
+                ->getOrCreateBookingCreateDto($request);
+        } catch (NoRoomsAvailableException $e) {
+            $this->addFlash('error', 'Leider sind für diese Reise aktuell keine Zimmer verfügbar.');
+            // TODO: Redirect to travel listing or hotel details page
+            throw $this->createNotFoundException('No rooms available for this travel.');
+        }
 
         // Enrich with fresh availability data
         $this->enrichWithFreshAvailabilities($bookingCreateDto);
@@ -93,7 +100,12 @@ class CreateStep2Controller extends AbstractController
     #[Route('/bookings/create/participants/refresh', name: 'app_booking_create_step_2_refresh', methods: ['POST'])]
     public function refreshParticipantForm(Request $request): Response
     {
-        $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+        try {
+            $bookingCreateDto = $this->bookingService->getOrCreateBookingCreateDto($request);
+        } catch (NoRoomsAvailableException $e) {
+            // For HTMX requests, return a simple error message
+            return new Response('<div class="text-red-700 p-4">Keine Zimmer verfügbar</div>', 400);
+        }
 
         // Enrich with fresh availability data
         $this->enrichWithFreshAvailabilities($bookingCreateDto);
diff --git a/src/Controller/Booking/CreateStep3Controller.php b/src/Controller/Booking/CreateStep3Controller.php
index 28189f6..065e19f 100644
--- a/src/Controller/Booking/CreateStep3Controller.php
+++ b/src/Controller/Booking/CreateStep3Controller.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Controller\Booking;
 
+use App\Exception\NoRoomsAvailableException;
 use App\Service\BookingService;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\Request;
@@ -31,7 +32,13 @@ class CreateStep3Controller extends AbstractController
     #[Route('/bookings/create/confirm', name: 'app_booking_create_step_3')]
     public function confirm(Request $request): Response
     {
-        $bookingCreateDto = $this->bookingCreateService->getOrCreateBookingCreateDto($request);
+        try {
+            $bookingCreateDto = $this->bookingCreateService->getOrCreateBookingCreateDto($request);
+        } catch (NoRoomsAvailableException $e) {
+            $this->addFlash('error', 'Leider sind für diese Reise aktuell keine Zimmer verfügbar.');
+            // TODO: Redirect to travel listing or hotel details page
+            throw $this->createNotFoundException('No rooms available for this travel.');
+        }
 
         // Validate step access
         $this->validateStepAccess($bookingCreateDto, 3);
diff --git a/src/Exception/NoRoomsAvailableException.php b/src/Exception/NoRoomsAvailableException.php
new file mode 100644
index 0000000..9d8a012
--- /dev/null
+++ b/src/Exception/NoRoomsAvailableException.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Exception;
+
+use Symfony\Component\HttpKernel\Exception\HttpException;
+
+/**
+ * Exception thrown when attempting to create a booking but no rooms are available.
+ *
+ * This exception is used to prevent users from entering the booking flow
+ * when there are no available rooms for the selected travel dates.
+ */
+class NoRoomsAvailableException extends HttpException
+{
+    public function __construct(int $dateId, int $hotelId, ?\Throwable $previous = null)
+    {
+        $message = sprintf(
+            'Leider sind für diese Reise aktuell keine Zimmer verfügbar (Travel ID: %d, Hotel ID: %d)',
+            $dateId,
+            $hotelId
+        );
+
+        parent::__construct(400, $message, $previous);
+    }
+}
diff --git a/src/Service/BookingService.php b/src/Service/BookingService.php
index a988f09..8335568 100644
--- a/src/Service/BookingService.php
+++ b/src/Service/BookingService.php
@@ -4,6 +4,7 @@ namespace App\Service;
 
 use App\BusProNet\Model\Room;
 use App\BusProNet\Model\Travel;
+use App\Exception\NoRoomsAvailableException;
 use App\Form\Model\BookingCreateDto;
 use App\Form\Model\RoomSelectionDto;
 use Symfony\Component\HttpFoundation\Request;
@@ -78,6 +79,11 @@ class BookingService
         $roomsIdsAndQuantities = $this->processRoomQuantities($request);
         $availableRooms = $travelData->getAvailableRooms();
 
+        // Prevent booking flow entry when no rooms are available
+        if (empty($availableRooms)) {
+            throw new NoRoomsAvailableException($dateId, $hotelId);
+        }
+
         $roomSelections = array_map(
             fn (Room $room) => $this->createRoomSelection($room, $roomsIdsAndQuantities),
             $availableRooms